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Support null values when parsing optional fields
We want to be more lenient in what we accept. Up until now, we've required that the JSON we parse come in a specific format: optional values don't exist. Unfortunately, things aren't so consistent in the real world. Instead of failing if we see an optional field that has a `null` value, we parse it as though the value coming in was `Data.Maybe.Nothing`. This is akin to how record-based values work (like `Option.set'`). Since this changes the semantics of parsing, this is a breaking change, and we should deal with it as such. With this change, we ought to be able to be used in more places without causing undue burden.
1 parent ee3090d commit b897f8e

8 files changed

+106
-6
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‎README.md

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@@ -330,6 +330,15 @@ We can give that a spin with some different JSON values:
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> parse """{"name": "Pat", "title": "Dr."}"""
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(Right (Option.fromRecord { name: "Pat", title: "Dr." }))
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> parse """{ "name": null }"""
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Right (Option.fromRecord {})
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> parse """{ "title": null }"""
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Right (Option.fromRecord {})
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> parse """{ "name": null, "title": null }"""
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Right (Option.fromRecord {})
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```
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We can also produce some different JSON values:
@@ -531,6 +540,15 @@ We can give that a spin with some different JSON values:
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> parse """{"name": "Pat", "title": "Dr."}"""
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(Right (Option.fromRecord { name: "Pat", title: "Dr." }))
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> parse """{ "name": null }"""
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Right (Option.fromRecord {})
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> parse """{ "title": null }"""
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Right (Option.fromRecord {})
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> parse """{ "name": null, "title": null }"""
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Right (Option.fromRecord {})
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```
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We can also produce some different JSON values:
@@ -828,6 +846,15 @@ We can give that a spin with some different JSON values:
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> readJSON """{"name": "Pat", "title": "Dr."}"""
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(Right (Option.fromRecord { name: "Pat", title: "Dr." }))
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> readJSON """{ "name": null }"""
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Right (Option.fromRecord {})
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> readJSON """{ "title": null }"""
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Right (Option.fromRecord {})
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> readJSON """{ "name": null, "title": null }"""
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Right (Option.fromRecord {})
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```
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We can also produce some different JSON values:
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> parse """{"name": "Pat", "title": "Dr."}"""
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(Right (Option.recordFromRecord { name: "Pat", title: "Dr." }))
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> parse """{ "name": "Pat", "title": null }"""
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Right (Option.recordFromRecord { name: "Pat" })
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```
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We can also produce some different JSON values:
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> parse """{"name": "Pat", "title": "Dr."}"""
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(Right (Option.recordFromRecord { name: "Pat", title: "Dr." }))
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> parse """{ "name": "Pat", "title": null }"""
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Right (Option.recordFromRecord { name: "Pat" })
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```
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Notice that we have to supply a `"name"` field in the JSON input otherwise it will not parse.
@@ -1474,6 +1507,9 @@ We can give that a spin with some different JSON values:
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> parse """{"name": "Pat", "title": "Dr."}"""
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(Right (Option.recordFromRecord { name: "Pat", title: "Dr." }))
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> parse """{ "name": "Pat", "title": null }"""
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Right (Option.recordFromRecord { name: "Pat" })
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```
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We can also produce some different JSON values:

‎src/Option.purs

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@@ -133,6 +133,7 @@ import Data.Argonaut.Decode.Error as Data.Argonaut.Decode.Error
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import Data.Argonaut.Encode.Class as Data.Argonaut.Encode.Class
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import Data.Codec as Data.Codec
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import Data.Codec.Argonaut as Data.Codec.Argonaut
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import Data.Codec.Argonaut.Compat as Data.Codec.Argonaut.Compat
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import Data.Either as Data.Either
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import Data.List as Data.List
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import Data.Maybe as Data.Maybe
@@ -605,9 +606,11 @@ else instance decodeJsonOptionCons ::
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Data.Either.Either Data.Argonaut.Decode.Error.JsonDecodeError (Option option)
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decodeJsonOption _ object' = case Foreign.Object.lookup key object' of
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Data.Maybe.Just json -> do
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value <- Data.Argonaut.Decode.Class.decodeJson json
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value' <- Data.Argonaut.Decode.Class.decodeJson json
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option <- option'
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Data.Either.Right (insert label value option)
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case value' of
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Data.Maybe.Just value -> Data.Either.Right (insert label value option)
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Data.Maybe.Nothing -> Data.Either.Right (insertField label option)
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Data.Maybe.Nothing -> do
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option <- option'
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Data.Either.Right (insertField label option)
@@ -1509,9 +1512,11 @@ else instance jsonCodecOptionCons ::
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decode object' = do
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option <- Data.Codec.Argonaut.decode option' object'
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case Foreign.Object.lookup key object' of
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Data.Maybe.Just json -> case Data.Codec.Argonaut.decode codec json of
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Data.Maybe.Just json -> case Data.Codec.Argonaut.decode (Data.Codec.Argonaut.Compat.maybe codec) json of
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Data.Either.Left error -> Data.Either.Left (Data.Codec.Argonaut.AtKey key error)
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Data.Either.Right value -> Data.Either.Right (insert label value option)
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Data.Either.Right value' -> case value' of
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Data.Maybe.Just value -> Data.Either.Right (insert label value option)
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Data.Maybe.Nothing -> Data.Either.Right (insertField label option)
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Data.Maybe.Nothing -> Data.Either.Right (insertField label option)
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encode ::
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true ->
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Control.Monad.Except.except case Control.Monad.Except.runExcept (Foreign.Index.readProp key foreign') of
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Data.Either.Left errors -> Data.Either.Left (map (Foreign.Index.errorAt key) errors)
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Data.Either.Right value' -> case Control.Monad.Except.runExcept (Simple.JSON.readImpl value') of
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Data.Either.Right value'' -> case Control.Monad.Except.runExcept (Simple.JSON.readImpl value'') of
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Data.Either.Left errors -> Data.Either.Left (map (Foreign.Index.errorAt key) errors)
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Data.Either.Right value -> Data.Either.Right (insert label value option)
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Data.Either.Right value' -> case value' of
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Data.Maybe.Just value -> Data.Either.Right (insert label value option)
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Data.Maybe.Nothing -> Data.Either.Right (insertField label option)
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false -> pure (insertField label option)
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where
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key :: String

‎test/HowTo.DecodeAndEncodeJSONWithOptionalValuesInPureScriptArgonaut.purs

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@@ -79,3 +79,15 @@ spec_parse =
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": "Pat", "title": "Dr." }""")
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(Data.Either.Right (Option.fromRecord { name: "Pat", title: "Dr." }))
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Test.Spec.it "doesn't fail a null name" do
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": null }""")
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(Data.Either.Right (Option.fromRecord {}))
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Test.Spec.it "doesn't fail for a null title" do
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Test.Spec.Assertions.shouldEqual
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(parse """{ "title": null }""")
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(Data.Either.Right (Option.fromRecord {}))
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Test.Spec.it "doesn't fail for a null name or title" do
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": null, "title": null }""")
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(Data.Either.Right (Option.fromRecord {}))

‎test/HowTo.DecodeAndEncodeJSONWithOptionalValuesInPureScriptCodecArgonaut.purs

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@@ -85,3 +85,15 @@ spec_parse =
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": "Pat", "title": "Dr." }""")
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(Data.Either.Right (Option.fromRecord { name: "Pat", title: "Dr." }))
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Test.Spec.it "doesn't fail a null name" do
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": null }""")
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(Data.Either.Right (Option.fromRecord {}))
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Test.Spec.it "doesn't fail for a null title" do
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Test.Spec.Assertions.shouldEqual
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(parse """{ "title": null }""")
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(Data.Either.Right (Option.fromRecord {}))
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Test.Spec.it "doesn't fail for a null name or title" do
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": null, "title": null }""")
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(Data.Either.Right (Option.fromRecord {}))

‎test/HowTo.DecodeAndEncodeJSONWithOptionalValuesInPureScriptSimpleJSON.purs

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@@ -58,6 +58,27 @@ spec_readJSON =
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Test.Spec.Assertions.shouldEqual
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(readJSON json)
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(Data.Either.Right (Option.fromRecord { name: "Pat", title: "Dr." }))
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Test.Spec.it "doesn't fail a null name" do
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let
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json :: String
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json = """{ "name": null }"""
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Test.Spec.Assertions.shouldEqual
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(readJSON json)
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(Data.Either.Right (Option.fromRecord {}))
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Test.Spec.it "doesn't fail for a null title" do
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let
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json :: String
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json = """{ "title": null }"""
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Test.Spec.Assertions.shouldEqual
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(readJSON json)
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(Data.Either.Right (Option.fromRecord {}))
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Test.Spec.it "doesn't fail for a null name or title" do
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let
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json :: String
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json = """{ "name": null, "title": null }"""
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Test.Spec.Assertions.shouldEqual
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(readJSON json)
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(Data.Either.Right (Option.fromRecord {}))
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spec_writeJSON :: Test.Spec.Spec Unit
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spec_writeJSON =

‎test/HowTo.DecodeAndEncodeJSONWithRequiredAndOptionalValuesInPureScriptArgonaut.purs

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@@ -71,3 +71,7 @@ spec_parse =
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": "Pat", "title": "Dr." }""")
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(Data.Either.Right (Option.recordFromRecord { name: "Pat", title: "Dr." }))
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Test.Spec.it "doesn't fail for null fields" do
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": "Pat", "title": null }""")
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(Data.Either.Right (Option.recordFromRecord { name: "Pat" }))

‎test/HowTo.DecodeAndEncodeJSONWithRequiredAndOptionalValuesInPureScriptCodecArgonaut.purs

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@@ -77,3 +77,7 @@ spec_parse =
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": "Pat", "title": "Dr." }""")
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(Data.Either.Right (Option.recordFromRecord { name: "Pat", title: "Dr." }))
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Test.Spec.it "doesn't fail for null fields" do
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": "Pat", "title": null }""")
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(Data.Either.Right (Option.recordFromRecord { name: "Pat" }))

‎test/HowTo.DecodeAndEncodeJSONWithRequiredAndOptionalValuesInPureScriptSimpleJSON.purs

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@@ -55,6 +55,10 @@ spec_parse =
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": "Pat", "title": "Dr." }""")
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(Data.Either.Right (Option.recordFromRecord { name: "Pat", title: "Dr." }))
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Test.Spec.it "doesn't fail for null fields" do
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Test.Spec.Assertions.shouldEqual
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(parse """{ "name": "Pat", "title": null }""")
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(Data.Either.Right (Option.recordFromRecord { name: "Pat" }))
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spec_writeJSON :: Test.Spec.Spec Unit
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spec_writeJSON =

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